Some applications need fast, low-latency communication where occasional packet loss is acceptable. Setting up connections for every small message wastes bandwidth and adds delay.
A service where packets are sent independently without connection setup, offering best-effort delivery with no guarantees of order, reliability, or flow control.
- No handshake or connection establishment before sending data
- Each packet (datagram) is treated independently with full addressing information
- Packets may take different network paths and arrive out of order or not at all
- No retransmission mechanism at this service layer
- No flow control or congestion control — sender transmits at will
- Stateless: neither endpoint maintains communication state
- No connection setup, teardown, or state maintenance
- Best-effort delivery with no guarantees
- Lower overhead and faster than connection-oriented
- Each packet routed independently
- Stateless operation at the service layer
- Built from: IP Protocol — network layer connectionless foundation
- Builds into: UDP — primary transport layer implementation
- Contrasts with: Connection-Oriented Service — reliable vs best-effort
- Related: Datagram — independent packet unit used
- Related: Best Effort Delivery — no delivery guarantees
- Applications must handle reliability at higher layers if needed
- Packet loss goes undetected unless application implements checking
- No backpressure mechanism — can overwhelm receiver or network
- Out-of-order delivery requires application-level reordering